IComparable Interface

Définition

Définit une méthode de comparaison généralisée spécifique au type qu'un type valeur ou une classe implémente pour ordonnancer ou trier ses instances.Defines a generalized type-specific comparison method that a value type or class implements to order or sort its instances.

public interface class IComparable
[System.Runtime.InteropServices.ComVisible(true)]
public interface IComparable
type IComparable = interface
Public Interface IComparable
Dérivé
Attributs

Exemples

L’exemple suivant illustre l’implémentation de IComparable et la méthode requise. CompareToThe following example illustrates the implementation of IComparable and the requisite CompareTo method.

using namespace System;
using namespace System::Collections;

public ref class Temperature: public IComparable {
   /// <summary>
   /// IComparable.CompareTo implementation.
   /// </summary>
protected:
   // The value holder
   Double m_value;

public:
   virtual Int32 CompareTo( Object^ obj ) {
   
      if (obj == nullptr) return 1;
      
      if ( obj->GetType() == Temperature::typeid ) {
         Temperature^ temp = dynamic_cast<Temperature^>(obj);

         return m_value.CompareTo( temp->m_value );
      }
      throw gcnew ArgumentException(  "object is not a Temperature" );
   }

   property Double Value {
      Double get() {
         return m_value;
      }
      void set( Double value ) {
         m_value = value;
      }
   }

   property Double Celsius  {
      Double get() {
         return (m_value - 32) / 1.8;
      }
      void set( Double value ) {
         m_value = (value * 1.8) + 32;
      }
   }
};

int main()
{
   ArrayList^ temperatures = gcnew ArrayList;
   // Initialize random number generator.
   Random^ rnd = gcnew Random;

   // Generate 10 temperatures between 0 and 100 randomly.
   for (int ctr = 1; ctr <= 10; ctr++)
   {
      int degrees = rnd->Next(0, 100);
      Temperature^ temp = gcnew Temperature;
      temp->Value = degrees;
      temperatures->Add(temp);
   }

   // Sort ArrayList.
   temperatures->Sort();
      
   for each (Temperature^ temp in temperatures)
      Console::WriteLine(temp->Value);
   return 0;
}
// The example displays the following output to the console (individual
// values may vary because they are randomly generated):
//       2
//       7
//       16
//       17
//       31
//       37
//       58
//       66
//       72
//       95
using System;
using System.Collections;

public class Temperature : IComparable 
{
    // The temperature value
    protected double temperatureF;

    public int CompareTo(object obj) {
        if (obj == null) return 1;
        
        Temperature otherTemperature = obj as Temperature;
        if (otherTemperature != null) 
            return this.temperatureF.CompareTo(otherTemperature.temperatureF);
        else
           throw new ArgumentException("Object is not a Temperature");
    }

    public double Fahrenheit 
    {
        get 
        {
            return this.temperatureF;
        }
        set {
            this.temperatureF = value;
        }
    }

    public double Celsius 
    {
        get 
        {
            return (this.temperatureF - 32) * (5.0/9);
        }
        set 
        {
            this.temperatureF = (value * 9.0/5) + 32;
        }
    }
}

public class CompareTemperatures
{
   public static void Main()
   {
      ArrayList temperatures = new ArrayList();
      // Initialize random number generator.
      Random rnd = new Random();
      
      // Generate 10 temperatures between 0 and 100 randomly.
      for (int ctr = 1; ctr <= 10; ctr++)
      {
         int degrees = rnd.Next(0, 100);
         Temperature temp = new Temperature();
         temp.Fahrenheit = degrees;
         temperatures.Add(temp);   
      }

      // Sort ArrayList.
      temperatures.Sort();
      
      foreach (Temperature temp in temperatures)
         Console.WriteLine(temp.Fahrenheit);
            
   }
}
// The example displays the following output to the console (individual
// values may vary because they are randomly generated):
//       2
//       7
//       16
//       17
//       31
//       37
//       58
//       66
//       72
//       95
Imports System.Collections

Public Class Temperature
    Implements IComparable
    ' The temperature value
    Protected temperatureF As Double

    Public Overloads Function CompareTo(ByVal obj As Object) As Integer _
        Implements IComparable.CompareTo
        
        If obj Is Nothing Then Return 1

        Dim otherTemperature As Temperature = TryCast(obj, Temperature)
        If otherTemperature IsNot Nothing Then
            Return Me.temperatureF.CompareTo(otherTemperature.temperatureF)
        Else
           Throw New ArgumentException("Object is not a Temperature")
        End If   
    End Function

    Public Property Fahrenheit() As Double
        Get
            Return temperatureF
        End Get
        Set(ByVal Value As Double)
            Me.temperatureF = Value
        End Set
    End Property

    Public Property Celsius() As Double
        Get
            Return (temperatureF - 32) * (5/9)
        End Get
        Set(ByVal Value As Double)
            Me.temperatureF = (Value * 9/5) + 32
        End Set
    End Property
End Class

Public Module CompareTemperatures
   Public Sub Main()
      Dim temperatures As New ArrayList
      ' Initialize random number generator.
      Dim rnd As New Random()
      
      ' Generate 10 temperatures between 0 and 100 randomly.
      For ctr As Integer = 1 To 10
         Dim degrees As Integer = rnd.Next(0, 100)
         Dim temp As New Temperature
         temp.Fahrenheit = degrees
         temperatures.Add(temp)   
      Next

      ' Sort ArrayList.
      temperatures.Sort()
      
      For Each temp As Temperature In temperatures
         Console.WriteLine(temp.Fahrenheit)
      Next      
   End Sub
End Module
' The example displays the following output to the console (individual
' values may vary because they are randomly generated):
'       2
'       7
'       16
'       17
'       31
'       37
'       58
'       66
'       72
'       95

Remarques

Cette interface est implémentée par les types dont les valeurs peuvent être triées ou triées.This interface is implemented by types whose values can be ordered or sorted. Elle nécessite que les types d’implémentation définissent CompareTo(Object)une méthode unique,, qui indique si la position de l’instance actuelle dans l’ordre de tri est antérieure, postérieure ou identique à un deuxième objet du même type.It requires that implementing types define a single method, CompareTo(Object), that indicates whether the position of the current instance in the sort order is before, after, or the same as a second object of the same type. L’implémentation de IComparable l’instance est appelée automatiquement par des méthodes Array.Sort telles ArrayList.Sortque et.The instance's IComparable implementation is called automatically by methods such as Array.Sort and ArrayList.Sort.

L’implémentation de la CompareTo(Object) méthode doit retourner un Int32 qui a l’une des trois valeurs, comme indiqué dans le tableau suivant.The implementation of the CompareTo(Object) method must return an Int32 that has one of three values, as shown in the following table.

ValueValue SignificationMeaning
Inférieure à zéroLess than zero L’instance actuelle précède l’objet spécifié par la CompareTo méthode dans l’ordre de tri.The current instance precedes the object specified by the CompareTo method in the sort order.
ZéroZero Cette instance actuelle se trouve à la même position dans l’ordre de tri que l’objet spécifié CompareTo par la méthode.This current instance occurs in the same position in the sort order as the object specified by the CompareTo method.
Supérieure à zéroGreater than zero Cette instance actuelle suit l’objet spécifié par la CompareTo méthode dans l’ordre de tri.This current instance follows the object specified by the CompareTo method in the sort order.

Tous les types numériques (tels Int32 que Doubleet) IComparableimplémentent, Stringcomme Charles actions DateTime, et.All numeric types (such as Int32 and Double) implement IComparable, as do String, Char, and DateTime. Les types personnalisés doivent également fournir leur propre implémentation IComparable de pour permettre aux instances d’objet d’être ordonnées ou triées.Custom types should also provide their own implementation of IComparable to enable object instances to be ordered or sorted.

Méthodes

CompareTo(Object)

Compare l'instance actuelle avec un autre objet du même type et retourne un entier qui indique si l'instance actuelle précède ou suit un autre objet ou se trouve à la même position dans l'ordre de tri.Compares the current instance with another object of the same type and returns an integer that indicates whether the current instance precedes, follows, or occurs in the same position in the sort order as the other object.

S’applique à